| 摘要 |
A numerically controlled nibbling machine in which the feed distance of a workpiece is limited by a release time during which a work tool is disengaged from the workpiece according to a predetermined number of strokes of the work tool per unit of time. The nibbling machine includes drive means for the work tool, means for controlling the feed rate of the workpiece with respect to the work tool, means for determining the release time in a single stroke of the work tool for every number of strokes of the tool per unit of time, and means for automatically determining minimum acceleration and deceleration of the workpiece required for travelling the feed distance and for forming a desired feed rate value for the workpiece from the release time and the feed distance of the workpiece. The improvement of the invention comprises the means for determining the release time further comprising switch means disposed in the path of the work tool for generating a stop command signal for the drive means for the work tool. The determining means further comprises means for selectively transmitting the stop command signal from the switch means to the control means when a predetermined, lowest speed of the drive means for the work tool is reached and stopping the work tool at an upper dead-center position of the work tool in the nibbling machine.
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